http://www.epa.gov/wastes/
We've made numerous reports concerning the use of Coal-fired power plant Fly Ash as a fine aggregate for various composite materials, most especially Portland Cement Concrete.
One of our favorites is that accessible on the West Virginia Coal Association web site, via:
US EPA Headquarters Housed in Coal Ash | Research & Development; which concerns, in part, the use of Coal Ash as an aggregate for Portland Cement Concrete, and, wherein we learn that Fly Ash has been used for such purposes "in several construction projects and prominent buildings, including the Ronald Reagan Government Office building, home to the Environmental Protection Agency (EPA) in Washington, D.C.".
As we've briefly documented, and as we will more fully explain in reports to follow, to make Coal Ash truly suitable for such uses, any residual and un-combusted Carbon in the Ash, which there is more of nowadays, due to certain types of pollution controls applied to Coal combustion processes, needs to be removed.
That is preferably accomplished by a process known as "Carbon Burn Out", wherein any residual Carbon in the Ash is itself actually oxidized and combusted, in a process that, in some cases, can not only be self sustaining, but, which can also generate some recoverable and useable heat energy.
We've made note of the Carbon Burn Out, or "CBO" process previously, as in our report of:
West Virginia Coal Association | Virginia Converts Coal Ash to Cash | Research & Development; which centered on the article:
"Dominion Recycling Center Turns Ash to Cash; The Virginia Pilot; November, 2006; Chesapeake (VA) - It looks like a really big igloo, or maybe an indoor skating rink. But Dominion Virginia Power says the new, domed structure next to its Chesapeake power station will make money, create jobs and help the environment. The waterfront facility, on the Elizabeth River just south of the Gilmerton Bridge, is an ash recycling center - the first of its kind in Virginia, and just the fourth in the nation. The facility acts like a big oven. It bakes black, carbon-laden fly ash into a kinder, gentler and paler byproduct that can be sold and made into concrete, roof tiling and construction blocks, among other alternative uses."
The United States Environmental Protection Agency, by all reports, does, or once did, encourage the recycling and productive reuse of solid Coal Combustion, or, more broadly, Coal Utilization, Byproducts, although they have, for whatever inexplicable reason, taken down or made inaccessible a web site they once had dedicated to that issue.
Herein, we wanted to document the fact that they did, at least at one time, officially approve of the reuse of Coal Ash, and, more specifically, of the "Carbon Burn Out" process which can not only recover some amount of energy, but, make Coal Ash more suitable for use as an aggregate in Portland Cement Concrete applications.
Comment follows excerpts from the initial link to an official US EPA statement of approval for the use of the Carbon Burn Out process, to beneficiate Coal Ash at the above-cited Dominion Virginia Power recycling center:
"United States Environmental Protection Agency; Washington, DC 20460
Office of Solid Waste and Emergency Response
July 21, 2011
Ms. Pamela F. Faggert; Vice President and Chief Environmental Officer;
Dominion Resource Services Inc.; 5000 Dominion Boulevard; Glen Allen, Virginia 23060
Dear Ms. Faggert:
Thank you for meeting with us on June 17, 2011, to discuss concerns related to the EPA's final rule entitled, Identification of Non-Hazardous Secondary Materials (NHSM) That Are Solid Wastes, 76 FR 15456 (March 21, 2011), You raised a number of questions regarding the regulatory status of materials being used in specific recirculation/reinjection processes and carbon burn-out (CBO) units at Dominion Power's facilities, that is, are they solid wastes or products under the NHSM rule?
First, the position expressed in this letter is based on information provided to the EPA during our June 17, 2011 meeting, an April 19, 2011 letter from PMI Technologies, LLC, and a June 16, 2011, email. Additionally, under the regulations, your company is responsible for determining whether a particular material is or is not solid waste.
Based on the information provided in our regulations (as augmented by the interpretation discussed in the preamble to the final rule and the rulemaking record), we believe the facts indicate that the units you describe constitute a continuous process in recovering energy from energy from coal and thus, these units would not be combusting solid wastes under the NHSM rule.
As described, the ash recirculation/reinjection system used at Dominion Power's fossil fuel-fired plants is a continuous, closed-loop process that is an integral component of the overall combustion process designed for fuel optimization and efficiency. Specifically, you indicated that the ash recirculation/reinjection is part of the overall boiler process design and is used as a fuel optimization process that maximizes the carbon burn-out in the ash - or put another way, maximizes the recovery of carbon from coal ... which improves the efficiency of the boiler.
Based on the description provided, we believe the heavier ash material that has an abundance of unburned carbon, does not exit the enclosed ash recirculation process and is returned to the furnace for further energy recovery to produce additional electricity is not a solid waste, but is the continual processing of the traditional fuel coal used by Dominion Power in its boilers. That is, recirculating or reinjecting the coal containing ash materials is an extension of the electricity producing operations, similar to stoker units and would not be considered a secondary material until the material exits the process or is otherwise discarded.
As described, CBO units are typically located at or adjacent to the coal-fired utility. High-carbon fly ash, as described by Dominion Power, generated at the utility is pneumatically conveyed from the power plant's existing silos to the CBO silo. The CBO unit incorporates a fluidized bed that further recovers energy from the residual carbon from high-carbon fly ash. Burning the high-carbon fly ash in CBO units generates sufficient heat to sustain combustion in the CBO unit without use of supplemental fuel other than as start up of the fluidized bed combustor unit. In addition, heat is recovered and transported back to the fossil fuel plant in the form of heated condensate or steam. Emissions from the CBO units are also sent back to the utility, and combined with the utility boiler emissions, which are routed through the boiler's air pollution control devices.
The preamble to the final rule ... indicated that high-carbon fly ash appeared to be a NHSM fuel that was burned to create both energy, as well as a marketable ingredient (low-carbon fly ash).
EPA determined that the fly ash going into the unit was clearly not being used as an ingredient, but was used to produce an ingredient.
(Signed) Suzanne Rudzinski, Director
Office of Resource Conservation and Recovery"
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We will have more on the technical details of the PMI Technologies and Dominion Power energy-recovering CBO Fly Ash beneficiation technology in reports to follow.
However, we wanted to document herein, that, the United States Environmental Protection Agency does affirm and confirm that Coal power plant Fly Ash can be made to be a "marketable" product, in a process that is not only self-sustaining, but, which can generate some useable amounts of byproduct heat energy.
The United States Environmental Protection Agency, in sum, herein confirms that:
The solid byproducts of our combustion of Coal for the generation of electrical power are not, necessarily, "solid wastes", but can, instead, be treated and regulated as "products".
The markets for Coal Ash products exist, as we have documented, and as we will further document.
We are, according herein to the US EPA, free to develop and expand at least some of those markets.
Why aren't we doing so in a more concerted and organized, more public, fashion?